What is the primary purpose of calculating precision in DXA?

• A. To assess the accuracy of a single measurement
• B. To evaluate the consistency of measurements over time
• C. To determine the machine's operational limits
• D. To track patient progress over time

Answer: (B)

The primary purpose of calculating precision in DXA (Dual-Energy X-ray Absorptiometry) is to evaluate the consistency of measurements over time. Precision refers to the degree to which repeated measurements under unchanged conditions yield the same results. In the context of bone densitometry, it is crucial to ensure that the same patient yields similar results across multiple scans, which helps in monitoring bone health accurately and identifying any changes or trends over time.

High precision means that even small changes in bone mineral density can be detected, which is vital for assessing the effectiveness of treatment or progression of osteoporosis. Without consistent measurements, it would be difficult to determine if a change in a patient's results is due to an actual change in bone density or merely the result of variability in measurement techniques.